Dressing device for sharpening apparatus grinding wheel



7 May 30, 1967 A. ANDERSON 4 DRESSING DEVICE FOR SHARPENING APPARATUSGRINDING WHEEL 5 sheets-Sheet 1 Filed Aug. 19, 1963 May 30, 1967 A.ANDERSON DRESSING DEVICE FOR SHARPENING APPARATUS GRINDING WHEEL 5Sheets-Sheet 2 Filed Aug. 19, 1963 m HE DRESSING DEVICE FOR SHARPENINGAPPARATUS GRINDING WHEEL 5 Sheets-Sheet :3

Filed Aug. 19, 1963 y 1967 A. ANDERSON 3,322,110

DRESSING DEVICE FOR SHARPENING APPARATUS GRINDING WHEEL Filed Aug. 19,1963 5 Sheets-Sheet 4 May 30, 1967 A, ANDERSON DRESSING DEVICE FORSHARFENING APPARATUS GRINDING WHEEL Filed Aug. 19, 1963 m: mzhm UnitedStates Patent 3,322,110 DRESSING DEVICE FOR SHARPENING APPARATUSGRINDING WHEEL Axel Anderson, Rockford, Ill., assignor to SundstrandCorporation, a corporation of Illinois Filed Aug. 19, 1963, Ser. No.302,963 3 Claims. (Cl. 125-11) This invention relates in general to agrinding wheel dressing device for a sharpening apparatus.

An object of this invention is to provide a new and improved dressingmeans for a grinding wheel so as to dress the wheel in such a manner asto render it capable of grinding a complete tooth form.

And still another object of the invention is to integrate a wheeldressing means as described in the preceding paragraph into a unitarybroach sharpening machine.

These and other objects of the invention will become more fully apparentfrom an examination of the following specification and drawings wherein:

FIGURE 1 is a prespective view of a broach sharpening machine embodyingthe principles of the present invention;

FIGURE 2 is a rear elevational view of the apparatus illustrated inFIGURE 1 with certain parts broken away for clarity;

FIGURE 3 is an enlarged view taken substantially as shown along line3--3 of FIGURE 2;

FIGURE 4 is an enlarged front elevational view of the dressing means forthe grinding wheel of the present invention;

FIGURE 5 is a view taken generally along line 55 of FIGURE 4;

FIGURE 6 is a view taken generally along line 6-6 of FIGURE 4;

FIGURE 7 is a view taken generally along line 77 of FIGURE 4;

FIGURE 8 is an enlarged view showing the grinding wheel engaging abroach tooth;

FIGURE 9 is an enlarged view taken along line 99 of FIGURE 2; and

FIGURE 10 is an enlarged view taken generally along line 1010 of FIGURE2.

While this invention is susceptible to embodiment in many differentforms, there is shown in the drawings and will herein be described indetail one specific embodiment, with the understanding that the presentdisclosure is to be considered as an exemplification of the principlesof the invention and is not intended to limit the invention to theembodiment illustrated. The scope of the invention will be pointed outin the appended claims.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views, thebroach sharpening machine of the present invention is shown generally at10, and includes a base 11 and a box-like housing or frame 12 affixedthereto. A slide 13 is mounted on the top of housing 12 for longitudinalreciprocating movement relative thereto, with the components foreffecting such movements mounted within housing 12. A broach holding andindexing mechanism indicated generally at 14 is mounted on base 11, anda grinding wheel assembly indicated generally at 15 is mounted on slide13 and is movable therewith into and out of grinding engagement with thebroach teeth, as will hereinafter become more fully apparent. A dressingdevice indicated generally at 16 is provided to dress the appropriateform of the grinding wheel.

As is best seen in FIGURE 2, the means for effecting the reciprocationof slide 13 includes a motor 20 aflixed to base 11, and having a pulley21 mounted on the output shaft thereof. A suitable switch 20a is mountedon the 3,322,110 Patented May'30, 1967 front face of housing 12 and isconnected in circuit with motor 20 for manual control thereof. Suitablefriction means 22 are provided on pulley 21 for driving engagement withthe outer periphery of a large diameter wheel 23. Wheel 23 is mounted ona shaft 24 which is journalled in the rear wall of housing 12, and whichextends into the interior thereof. A pinion 25 is fixed to the inner endof shaft 24, and drivingly engages a gear 26 which is rotatably mountedin the housing rear wall by a shaft 26a. A link 27 is pinned at one endto gear 26 and at the other end to an arm 28 that is aflixed to slide 13to comprise a slide crank mechanism for reciprocating slide 13. Wheel 23extends above the upper surface of slide 13, as can be seen in bothFIGURE 1 and FIGURE 2, and thus is readily accessible for manualoperation so that the movement of the slide 13 can be effected eitherautomatically or manually as desired.

Grinding wheel assembly 15 includes a motor 30 (FIG- URE 2) suitablysupported upon a motor support arm 31. A suitable switch 30a isconnected in circuit with motor 30 for manual control thereof. A shaft32 is rotatably mounted in the opposed end of motor support arm 31, witha pulley 33 being fixed to the rearward end of shaft 32. A grindingwheel 36, formed of a suitable abrasive material, is fixed to theforward end of shaft 32 for rotation therewith. An endless belt 35 istrained over a pulley 34 fixed to the motor output shaft to drive thepulley 33 and shaft 32.

Means are provided for adjusting the vertical elevation of grindingwheel 36, and include an adjusting arm pivotally mounted at between apair of spaced blocks 41 and 42 which are secured to the upper surfaceof slide 13 by bolts or the like, not shown. A flattened portion 37 ofmotor support arm 31 is seated upon a planar shelf portion 42 at theforward end of adjustment arm 40, with an alignment pin 43 fixed inadjustment arm 40 and extending upward through a suitable opening insupport arm 31. Movement of arm 40 about its pivot 45 is effected by athreaded member 46 that engages a correspondingly threaded hole in theend of arm 40, and bears against the upper surface of slide 13. A handle47 is aflixed to the upper end of member 46 for manual operationthereof. Undesirable movement of grinding wheel 36 once it is in theadjusted position is resisted by a spring 48 that is biased between theupper surface of arm 40 and a washer 49a that is positioned under thehead of a screw 49, which is threaded into the upper surface of slide13.

Broach holding and indexing mechanism 14 includes a vertically extendingupright 50 having a stand 51 positioned on base 11. Stand 51 includes atransversely extending upright portion 51:: terminating in alongitudinally extending upright portion 51b. A transversely extendingmember 52 is positioned adjacent stand 51 and includes an upraisedportion 54 adjacent the rear edge 55 of base 11. An arm 56 is secured tothe upper surface of upraised portion 54 and extends outwardlytherefrom, as is best seen in FIGURE 2.

Broach holding and indexing mechanism 14 further includes a shaft 60which extends toward grinding mech anism 15 from the upper portion ofupright 50 at generally right angles thereto. An indexing plate 61 inthe form of a segment is swingably mounted about shaft 60 by a pair ofupwardly converging arms 62 and 63 which are joined at a hub 64 that ispivotally mounted on shaft 60. Indexing segment 61 is connected to arms62 and 63 by a pair of suitable connector members 65, one of which isshown in FIGURE 2. Indexing segment 61 includes two spaced apart rows ofteeth 66 and 67 with the teeth being disposed on the circumference of acircle, with the shaft 60 at the center, and with the spacing betweenthe teeth corresponding to the spacing between the teeth on thebreaching tool to be sharpened, as

'limit the swinging movement of indexing plate 61 in one direction.

A switch housing 70 is secured to upright 50, and the switch isconnected into the circuit of motor 20 by cable 73. A switch operator 71extends outwardly from upright 50 into the line of travel of a tripelement 73 secured to arm 63. Thus, when indexing plate 61 reaches theend of a grinding cycle, trip element 73 will engage switch operator 71to stop motor 20.

The means for holding the broaching tools will be best understood from aconsideration of FIGURE 1 and FIGURE 3, and includes a backing plate 75fixed to indexing plate 61. A pair of identical parallel posts 76 and 77are mounted at spaced apart points on backing plate 75. A wedge member78 includes a generally horizontally disposed lower surface 78a which isslida-bly mounted on posts 76 and 77, and an inclined face 79 disposedat an appropriate angle, as for example 30. A longitudinally extendingslot 80 is provided in wedge 78, and is disposed in substantialparallelism with a line drawn through the centers of posts 76 and 77.

The type of broaching tool with which this invention is particularlyconcerned is set forth in detail in copending application, Ser. No.142,088. A typical broaching tool is shown in broken line position at 90in FIGURE 3 and includes a generally fiat blade shaped body with aseries of teeth 91 along one edge thereof arranged to define a curvedcutting profile with the specific form being shown as an arc of acircle. The body of the blade is shaped to have a rear edge 92, that isadapted to be seated upon inclined surface 79, and a side edge 93arranged at an acute angle of approximately 60 and with the side edge 93being generally parallel to a face 94 of a cutting tooth. The back edge92 of the blade body is generally parallel to a tangent of the curvedcutting profile intermediate its ends. As will hereinafter become morefully apparent, blades 90 are sharpened along a line that is generallyparallel with edge 93 so that the blades will have the same generalconfiguration after they are sharpened. The blade edge 93 is positionedagainst a post 81 which extends outwardly from backing plate 75 andserves as a stop means for the blade 90. A'locking member 82, having aknob 83, impales slot 80 and engages a suitable threaded opening inbacking plate 75 to lock the wedge 78 in the appropriate adjustedposition. Blade 90 is held in place against post 81 by a clamping bar 84having locking members 85 and 86 at opposed ends thereof threadablyengaging suitable openings in backing plate 75. It should be understoodthat while a single blade has been referred to above, the holding meansare capable of accommodating a plurality of blades for simultaneoussharpening thereof.

Means are provided to vertically adjust the height of the broachmounting means, to the correct setting for the amount of stock to betaken off during the grinding cycle. To this end, a vertically elongatecentral opening 100 is formed inthe upper portion of upright 50, with anI-shaped block 101 mounted therein for vertical 'movement relative toupright 50. Shaft 60 is mounted in block 101 and is verticallyadjustable therewith. A cap 102 is secured to the upper surface ofupright 50, and a threaded member 103 extends through a clearanceopening in cap 102, and into a suitably threaded opening in block 101. Aknob 105'is secured to the upper end of member 103 for manual adjustmentthereof. A calibrated scale 104 is provided on cap 102, so that asmember 103 is adjusted by knob 105, the exact vertical elevation ofshaft 60 may be determined. Means are provided to limit the totalvertical adjustment of the broach mounting' means so that the finalgrinding cycle will take place at a fixed elevation, and as shown inFIGURE 3, comprises a bolt 99 that is threaded into the upper surface 4of block 101 to engage cap 102 at the upper limit of travel of block101. Volt 99 may be adjusted to vary the.

position of the stop as desired.

Means are provided for determining the position of the broach toolrelative to the grinding wheel 36, and

includes a gauge arm 106 having a tubular sleeve 107 swingably mountedon shaft 60. A feeler member 108 is secured to one end of arm 106, andincludes a feeler surface 109 disposed on an arc of a circlecorresponding to the arc of broach teeth 91. A sleeve 110 is fixed tosleeve 107 on the opposite side of shaft 60 from feeler member 108.Sleeve 110 includes a longitudinally extending bore 111 in which athreaded release member 112 is received. Member 112 is provided with aknob 116 for manual operation thereof. A nut 113 is threaded on releasemember 112 and serves as a stop for one end of a compression spring 114.A threaded fitting 115 is mounted on release member 112 adjacent the endof sleeve 110 and serves as a stop means for the other end of spring114. It will be readily apparent that the retraction of release member112 by pulling out knob 116 will release gauge arm 106 forswinging-movement relative to '26, an upwardly inclined area 122extending generally 90 around gear 26 and terminating in a flattenedportion 123, and a downwardly inclined area 124 extending generally 90around gear 26. A cam follower in the form of a roller 125 mounted onthe end of a follower arm 126 is adapted to ride around theaforedescribed cam as gear 26 is rotated by pinion 25. Ann 126 ismounted for pivotal movement about vertically extending pin 127. Aspring 128 is secured to arm 126 between follower and pivot 127, and tothe adjacent housing wall, to resist clockwise movement of arm 126 asviewed in FIGURE 9. Arm 126 extends outwardly through a suitable opening129 provided in the end wall of housing 11 and includes at the outer endthereof a suitable driver element 130-. A spring 131 is secured at oneend to a vertically extending post 132, and at the other end to arm 126adjacent driver,130 to resist counterclockwise movement of arm 126 asviewed in FIGURE 9.

A pair of side by side pawl members 135 and 136 are positioned invertical alignment with the rows of teeth 66 and 67, respectively, ofindex plate 61. Pawls 135 and 136 are mounted for pivotal movementrelative to the upraised portion 54 of transverse member 52 by a pin 137which impales suitable aligned apertures in pawls 135 and 136, and whichthreadably engages a suitably threaded hole in upraised portion 54. Asis best seen in FIGURE 3, pawls 135 and 136 extend outwardly from base11 a Sllfli'. cient distance so as to be readily accessible for manualoperation. Pawls 135 and 136 include upwardly extending tooth members138 and 139 which engage the adjacent teeth on the index plate rows 66and 67 respectively. Pawl 135 includes a vertically extending groove 140that is opened toward housing 12, and is adapted to be engaged by thedriving portion 130 of arm 126. Pawl 135 also includes a longitudinalslot 141 which receives pin 137, so that pawl 135 is slidably mountedrelative to pawl 136. Thus, as arm 126 pivots counterclockwise as viewedin FIGURE 9, pawl 135 will be advanced to the left as viewed in FIGURE3, and index plate 61 will be indexed one tooth length, with pawl 136pivoting to allow the passage of the teeth on row 67 of index plate 61to pass thereunder. When arm 126 rotates clockwise as viewed in FIGURE9, pawl 135 will be moved to the right as viewed in FIGURE 3, with thetooth 139 on pawl 136 engaging the adjacent tooth on row 67 of indexplate 61 to hold index plate 61 in position. As pawl 135 moves to theright as viewed in FIGURE 3, it will pivot around pin 137 to allow thetooth 138 to pass under the adjacent tooth on the row of teeth 66 ofindex plate61. As pawl 135 moves to the right as viewed in FIGURE 3,pawl 136 remains stationary with tooth 138 engaging the adjacent toothon row 67 to hold index plate 61 in position. Arm 126 moves clockwise asviewed in FIGURE 9 when follower 125 rides from portion 123 down theinclined portion 124 and arm 126 moves in the counterclockwise directionas follower 125 rolls up incline 122, so that the index plate 61 will beindexed one tooth for each rotation of gear 26.

Referring now to FIGURE 4 through FIGURE 8, the dressing means 16 forgrinding wheel 36 is set forth in detail, and includes a mounting block150 secured to the front face of housing 12 as by bolts 151 and 152.Dowel pins are provided at 153 and 154 to accurately locate the supportblock 150 relative to the housing 12. A central recess 155 is providedin the forward face of block 150, and defines a vertical slideway forreception of the base 156 of the dresser assembly. Base 156 includes apair of spaced apart vertical slots 157 and 158 which receive the shanksof bolts 159 and 160 therein respectively, with bolts 159 and 160 beingreceived in suitably threaded horizontally aligned openings in block150, to lock base 156 at the desired elevation. A screw 161 isthreadably received in a tab 162 that extends outwardly from recess 155,with the end of screw 161 engaging the bottom surface of base 156 toprovide an incremental adjusted means for the dresser assembly.

A generally cylindrically shaped member 163 is secured to the upperportion of base 156 with its axis being disposed in a horizontal plane.Member 163 has an axially extending bore 164 in which a cylindricalmember 165 is rotatably mounted. A longitudinally extending bore 167 isprovided in member 165, with the axis 168 of bore 167 being spaced fromand parallel with the axis 166 of memher 165. A generally cylindricalmember 169 is positioned in bore 167, and is rotatable about axis 168.

Member 169 extends outwardly from the left hand end of sleeve 163, asviewed in FIGURE 4 and FIGURE 6, and includes a narrowed end portion 170having a threaded hole 171 extending transversely therethrough. A bolt172 is threadably received in hole 171, and is provided with a diamondor other suitable dressing member 173 at one end thereof. A nut 174 isprovided to hold the member 172 in the proper position on portion 170. Ahandle 175 is secured to the right hand end of member 169, as viewed inFIGURE 4 and FIGURE 6, as by a bolt 176. Handle 175 is bent as at 177 toprovide a readily accessible gripping portion 178. A stop pin 180 ismounted on member 165, and is engageable with the upper surface 179 ofhandle 175. A second handle 181 is secured to the left hand end ofmember 165, as viewed in FIGURE 4 and FIG- URE 6, as by a bolt 182, andincludes a readily accessible gripping portion 183. A stop 184 isprovided on the left hand end of sleeve 163, as viewed in FIGURE 4 andFIG- URE 6, and is adapted to be engaged by the upper surface 185 ofhandle 181.

With particular reference to FIGURE 8, it will be noted that thegrinding surface of grinding wheel 36 includes two arcuate grindingportions 360 and 36b, which function to grind the entire tooth form of atooth 91 of the broach 90. To dress the grinding surface of wheel 36,handles 175 and 181 are gripped with the right and left handsrespectively. While lightly holding handle 181, handle 175 is liftedagainst stop 180 overcoming the hand holding pressure on handle 181, torotate member 165 until the upper surface 185 of handle 181 contactsstop 184. This movement swings the diamond 173 through an are slightlyin excess of 180, and dresses the grinding wheel portion 36a. Handle 181is then held firmly against stop 184, and handle 175 is swung downwardlyabout pivot 168. This movement causes diamond 173 to swing in an arc ofapproximately 180 to grind the grinding wheel portion 36b. Handle 181 isthen returned to the down position illustrated in the drawings, and thedressing of the grinding wheel 36 is completed.

To operate the broach sharpening machine, the elevation of grindingwheel 36 is first fixed by the manual operation of knob 47. Dresserassembly 16 is then positioned at the proper elevation, and bolts 159and 160 are tightened. Index plate 61 is then indexed to the positionshown in FIGURE 1, with trip elements 73 having tripped switch actuator71. The blade or blades are then positioned as shown in FIGURE 3, andwedge 78 is adjusted until feeler- 108 makes light contact with thebroach teeth 91. Knobs 83, 85 and 86 are then tightened to secure wedge78 and clamp bar 84 respectively, and gauge bar 106 is swung to thehorizontal position illustrated in FIGURE 3. Slide 13 is then positionedby manual operation of wheel 23 to align a suitable pointer 190 (FIGURE2), that is afiixed to the rear edge of slide 13, with a mark (notshown) on wheel 23 to properly position the dressing member 173 relativeto the grinding Wheel 36. Switch 30a is then actuated to rotate grindingwheel 36, and the dresser assembly '16 is operated as set forth above todress the grinding configuration of wheel 36. Index plate 61 is thenlifted slightly to allow pawl teeth 138 and :139 to be manually movedout of engagement with the adjacent teeth on the indexing plate so thatthe indexing plate can be swung into the position shown in FIGURE 3 witharm 63 positioned in engagement with stop 68. The machine is then readyfor the start of either manual or automatic grinding.

In the manually operated grinding cycle, hand wheel 23 is manuallyrotated to reciprocate slide 13 and index indexing plate 61 from toothto tooth. The automatic grinding cycle is started by actuating switch20a, and the grinding wheel 36 will sequentially pass through each toothspace on the broaching tool to be sharpened until switch actuator 71 istripped by element 73 to complete one grinding cycle. Hand knob is thenturned to raise the broaching tool to be sharpened for additionalgrinding. The operation is repeated until stop 99 contacts cap 102. Atthis position the grinding wheel 36 should be redressed for the finalgrinding cycle. It will be noted that during the initial grinding passesmore stock is removed at the end of the blades than is removed in thecenter, because the swing radius of the blades is different from thefinal grind radius.

Since dresser assembly .16 is locked at a fixed location on housing 12,the configuration of the grinding wheel 36 is dressed in fixed relationto the base 11. Stop 99 is fixed in relation to the wheel dresser 16,and thus the finish radius of the broach teeth 191 is established by themachine and not by the operator. A suitable gauge may be provided todetermine the position of diamond 173 relative to cylindrical member:169 so that the diamond may be periodically adjusted to compensate forwear thereof, and thus assure the production of the desired broach toothform. From the foregoing it should be apparent that each of the objectsof the invention have been fully achieved.

I claim:

1. A dressing device for a grinding wheel having first and secondtangent arcuate portions, comprising: a sleeve having opposite ends andhaving an axially extending first bore; a first member pivotally mountedin said first bore and having opposite ends; a longitudinally extendingaxially offset second bore in said member, said member beingsubstantially the same length as said sleeve and said second boreextending from end-to-end of said member; a second member pivotallymounted in said second bore and having opposite ends; a stop projectingoutwardly from one end of said sleeve; a first handle secured to one endof said first member and movable in a plane perpendicular to the axis ofsaid bores, said first handle having a surface engageable with saidstop; an abutment projecting outwardly from the opposite end of saidfirst member; a second handle secured to one end of said second. memberand movable in a plane parallel to the plane of movement of said firsthandle, said second handle having a surf-ace engageable with saidabutment for rotating said first member; a dressing member secured tothe opposite end of said second member; said stop being located on saidsleeve in a position whereby said dressing member is moved through afirst are as said first member is rotated by engagement of said secondhandle surface with said abutment when said second handle is pivoted inone direction until said first handle surface engages said stop, andsaid dressing member is moved through a second arc tangent to said firstarc when said second handle is pivoted in an opposite direction to pivotsaid second member while said first handle surf-ace is held against saidstop. 7

2. A dressing device as defined in claim 1 wherein said sleeve isgenerally cylindrical, and said first and second members are generallycylindrical from end-to-end thereof.

8 3. A dressing device as defined in claim 1 wherein said opposite endof said second member extends outwardly of said sleeve.

References Cited UNITED STATES PATENTS 1,104,589 7/1914 Ward et a1.51-34 1,573,153 2/1926' Garrison.

1,831,204 11/1931 Stauder 76-42 X 1,900,943 3/1933 Miller.

1,979,536 11/ 1934 Edgar 125-11 2,113,287 4/ 1938 Baldenhofer 51-562,301,610 11/ 1942 Brady 125-11.4 2,376,959 5/1945 Christle 125 11.4

HAROLD D. WHITEHEAD, Primary Examiner.

LESTER M. SWINGLE, ROBERT C. RIORDON,

Examiners. I. A. MATHEWS,-Assistant Examiner.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,322, 110 Dated May 30, 1967 Invent fl Axel Anderson It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 5, delete "Illinois" and insert -Delaware SIGNED ANDSEALED MAR 101970,

o wmlm E. suuum, .m.

Attesting Officer Commissioner of Patents

1. A DRESSING DEVICE FOR A GRINDING WHEEL HAVING FIRST AND SECONDTANGENT ARCUATE PORTIONS, COMPRISING: A SLEEVE HAVING OPPOSITE ENDS ANDHAVING AN AXIALLY EXTENDING FIRST BORE; A FIRST MEMBER PIVOTALLY MOUNTEDIN SAID FIRST BORE AND HAVING OPPOSITE ENDS; A LONGITUDINALLY EXTENDINGAXIALLY OFFSET SECOND BORE IN SAID MEMBER, SAID MEMBER BEINGSUBSTANTIALLY THE SAME LENGTH AS SAID SLEEVE AND SAID SECOND BOREEXTENDING FROM END-TO END OF SAID MEMBER; A SECOND MEMBER PIVOTALLYMOUNTED IN SAID SECOND BORE AND HAVING OPPOSITE ENDS; A STOP PROJECTINGOUTWARDLY FROM ONE END OF SAID SLEEVE; A FIRST HANDLE SECURED TO ONE ENDOF SAID FIRST MEMBER AND MOVABLE IN A PLANE PERPENDICULAR TO THE AXIS OFSIAD BORES, SAID FIRST HANDLE HAVING A SURFACE ENGAGEABLE WITH SAIDSTOP; AN ABUTMENT PROJECTING OUTWARDLY FROM THE OPPOSITE END OF SAIDFIRST MEMBER; A SECOND HANDLE SECURED TO ONE END OF SAID SECOND MEMBERAND MOVABLE IN A PLANE PARALLEL TO THE PLANE OF MOVEMENT OF SAID FIRSTHANDLE, SAID SECOND HANDLE HAVING A SURFACE ENGAGEABLE WITH SAIDABUTMENT FOR ROTATING SAID FIRST MEMBER; A DRESSING MEMBER SECURED TOTHE OPPOSITE END OF SAID SECOND MEMBER; SAID STOP BEING LOCATED ON SAIDSLEEVE IN A POSITION WHEREBY SAID DRESSING MEMBER IS MOVED THROUGH AFIRST ARC AS SAID FIRST MEMBER IS ROTATED BY ENGAGEMENT OF SAID SECONDHANDLE SURFACE WITH SAID ABUTMENT WHEN SAID SECOND HANDLE IS PIVOTED INONE DIRECTION UNTIL SAID FIRST HANDLE SURFACE ENGAGES SAID STOP, ANDSAID DRESSING MEMBER IS MOVED THROUGH A SECOND ARC TANGENT TO SAID FIRSTARC WHEN SAID SECOND HANDLE IS PIVOTED IN AN OPPOSITE DIRECTION TO PIVOTSAID SECOND MEMBER WHILE SAID FIRST HANDLE SURFACE IS HELD AGAINST SAIDSTOP.